Re: dmaengine: dw-dmac: Custom cyclic API (Why?)

From: Andy Shevchenko
Date: Mon Jan 02 2017 - 03:38:07 EST


On Fri, 2016-12-30 at 12:05 +0000, Jose Abreu wrote:
> ++dw-dmac Maintainers
>
>
> On 30-12-2016 11:32, Jose Abreu wrote:
> > Hi All,
> >
> >
> > I am going to work with dw-dmac AHB controller and I wanted to
> > use SND_DMAENGINE_PCM. In order to use this, a standard DMA
> > driver with cyclic support is needed. I found out that dw-dmac is
> > capable of cyclic transfers but instead of using the DMA engine
> > standard cyclic API it uses a custom API. Is there any specific
> > reason for this? What is the effort to change the custom API to a
> > standard DMA engine cyclic API?
> >

Because it was a predecessor of generic implementation.

I used to have some semi-finished patch to switch to generic API, though
at that point I had no means to test it.

Since I eventually got iDMA 32-bit, which is used as LPE Audio DMA
engine, support in my branch I might test it in the future, though I
think someone else would be much faster than me.

So, I can share whatever I have to the topic with someone who is really
interested to do that task.

--
Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Intel Finland Oy